Human genetic code linked to biological ageing identified for first
time

7 February 2010

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An Anglo Dutch team of scientists has identified for the first
time definitive genetic code associated with biological ageing in
humans.

The team analyzed more than 500,000 genetic variations across the
entire human genome to identify the 'variants', which are located near a
gene called TERC.

The study, which is published in Nature Genetics, was
conducted by researchers from the University of Leicester and King’s
College London, working with University of Groningen in the Netherlands,
and was funded by The Wellcome Trust and the British Heart Foundation.

British Heart Foundation Professor of Cardiology at the University of
Leicester Professor Nilesh Samani, of the Department of Cardiovascular
Sciences, who co-led the project, explained that there are two forms of
ageing — chronological ageing, ie how old you are in years and
biological ageing whereby the cells of some individuals are older (or
younger) than suggested by their actual age.

He said: “There is accumulating evidence that the risk of
age-associated diseases including heart disease and some types of
cancers are more closely related to biological rather than chronological
age.

“What we studied are structures called telomeres which are parts of
one’s chromosomes. Individuals are born with telomeres of certain length
and in many cells telomeres shorten as the cells divide and age.
Telomere length is therefore considered a marker of biological ageing.

“In this study what we found was that those individuals carrying a
particular genetic variant had shorter telomeres ie looked biologically
older. Given the association of shorter telomeres with age-associated
diseases, the finding raises the question whether individuals carrying
the variant are at greater risk of developing such diseases.”

Professor Tim Spector from King’s College London and director of the
TwinsUK study, who co-led this project, added: “The variants identified
lies near a gene called TERC which is already known to play an important
role in maintaining telomere length. What our study suggests is that
some people are genetically programmed to age at a faster rate.

"The effect was quite considerable in those with the variant,
equivalent to between 3-4 years of biological ageing as measured by
telomere length loss. Alternatively genetically susceptible people may
age even faster when exposed to proven ‘bad’ environments for telomeres
like smoking, obesity or lack of exercise, and end up several years
biologically older or succumbing to more age-related diseases. “